In general, heating cooking devices are divided into the heating cooking devices using gas and the heating cooking devices using electricity as heating sources.
The heating cooking devices using electricity include the heating cooking devices by induction heating (IH (Induction Heating) cooking devices) and the heating cooking devices by radiation heating represented by an electric stove and a radiant heater.
An electric stove and a radiant heater have the features that the manufacture cost thereof is about 1/10 and permit use of cooking containers such as a pot of any material, as compared with an IH cooking device, but do not have safety devices for objects being cooked (for example, prevention of a deep-frying oil fire, and burning and sticking, and prevention of cooking without a pan or a pot), and further, are not equipped with the function of cooking control (deep-frying, and water boiling).
The reasons why replacement purchases of cooking devices using electricity from gas cooking devices using fossil fuel do not advance while there is clamor for reduction of CO2 include the fact that IH cooking devices fully equipped with safety devices and cooking control functions are more expansive as compared with gas devices, and that electric stoves and radiant heaters that are less expensive are accompanied by inconveniences such as being incapable of cooking fried food such as deep-fried food because the safety devices thereof are insufficient, or incapable of performing cooking control.
As shown in FIG. 12, in an IH cooking device 200, a plurality of mushroom-shaped temperature sensors 203 for detecting a temperature of an object being cooked are bonded onto a bottom surface of a top plate 204 of glass on which a cooking container P is placed, and an infrared ray sensor 205 is placed in a center, in addition to a temperature sensor 202 for detecting a temperature of an IH heating coil 201. Further, a vibration sensor 206 is placed on the bottom surface of the top plate 204 to detect boiling vibration of water boiling. As above, the IH cooking device 200 can sensitively respond to a use situation of a person who cooks by causing one kind of a plurality of kinds of detection means or the plurality of kinds of detection means in combination to function.
FIG. 13 shows a structure of a heating cooking device 100 including a general radiant heater.
In a heater unit 20, a lower part of a heating coil 21 is buried and fixed into a base portion 23 made of a heat insulator, and a metallic cover 25 protects and holds a bottom surface of the base portion 23. At a peripheral edge of the base portion 23, a spacer 24 is raised toward a top plate 11. The spacer 24 is provided to provide a predetermined space between the base portion 23 and the top plate 11. The spacer 24 may be formed integrally with the base portion 23, or may be produced as a separate piece and assembled to the base portion 23. The heater unit 20 is pressed against the top plate 11 of glass by springs 27 that support an undersurface thereof. Accordingly, the heater unit 20 can be raised and lowered with expansion and contraction of the springs 27. This is to avoid breakage of the base portion 23 and the top plate 11 due to strain by thermal expansion and contraction which occur to the base portion 23, a cover 25 and the top plate 11 with rise and decline of the temperature of the heating coil 21. Further, the springs 27 also perform action of absorbing deflection of the top plate 11 when a cooking container such as a pot drops.
The heating cooking device 100 includes a thermostat 29 on a top surface of the base portion 23 (for example, Patent Document 1 and Patent Document 2). The thermostat 29 is provided at the high power type heating cooking device 100 which has the heating coil 21 with strong power and can perform rapid heating. This is because unless output of the heating coil 21 is controlled, the temperature of the top plate 11 is likely to exceed the heatproof temperature of the glass. Therefore, the temperature of the heating coil 21 is controlled by the thermostat 29, whereby the temperature of the top plate 11 does not exceed the heatproof temperature of the glass. Accordingly, the thermostat 29 is not needed in the heating cooking device 100 in which the heating coil 21 has low power.